Nuclear magnetic resonance spectroscopy will be used to study biological supramolecular structures, in particular protein-nucleic acid complexes. The systems under investigation are the filamentous bacteriophage fd and the DNA unwinding protein coded for by gene 5 of this phage. The research is designed to further develop the techniques and theories of NMR for the study of solid and quasi-solid materials. These will then be applied to the biochemical systems to describe in detail DNA-protein interactions and protein structure and dynamics for large, well-organized protein aggregates such as the virus capsid.